Built-in tension spring to hold your mags in place and to allow the case to accommodate all caliber double column mags. The proprietary belt clip is designed as a clip-on but is as secure as a solid belt loop, thanks to the aggressive talon and special Carbon-Fiber material. The belt clip can be easily removed to allow the case to be carried on a Blackhawk Dual Rail Accessory Platform. Holds 9mm to .40 caliber staggered column magazines including polymer-body designs. Model 410500P